Coronary atherosclerosis is a major case of death in IDDM. IDDM accelerates coronary atherosclerosis in middle age adults. However, the effect of IDDM in adolescents and young adults is not known. The investigators hypothesize that IDDM accelerates coronary atherosclerosis, eliminates female gender protection, and is an important risk factor for coronary atherosclerosis in adolescents and young adults. This proposal will test these hypotheses by documenting coronary artery calcifications, known cardiovascular risk factors, glycemic control, and duration of diabetes in a population-based study of 93 subjects with IDDM and age, gender, and race matched controls >/= 18 and </= 29 years of age. Establishing the presence of coronary artery atherosclerosis and its risk factors in this population is important clinical information in order to design early, successful interventions focused on individuals at greatest risk to suffer subsequent morbidity and mortality. This proposal is also a further step by the investigators to establish a model of diabetic heart disease which combines the assessment of cardiovascular and diabetic risk factors with the pathophysiology of the coronary arteries and the myocardium. The investigators will then use this model to define the development, to establish further risk, and to assess the efficacy of interventions to prevent or limit heart disease in IDDM.